May 21 – Kublai sends his envoy Hao Jing to negotiate with Song Dynasty Chancellor Jia Sidao, after the small force left by Kublai south of the Yangtze River is destroyed, by a Chinese army of the Southern Song Dynasty. Chancellor Jia Sidao imprisons the entire embassy of Kublai. This slight will not be forgotten by Kublai, but he is unable to assault the Song, due to the civil war with his rival brother Ariq Böke.

German musical theoristFranco of Cologne publishes Ars Cantus Mensurabilis, in which he advances a new theory of musical notation, in which the length of a musical note is denoted by the shape of that note, a system still used today.

1.
12th century
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As a means of recording the passage of time, the 12th century is the period from 1101 to 1200 in accordance with the Julian calendar in the Common Era. In the history of European culture, this period is considered part of the High Middle Ages and is called the Age of the Cistercians. In Song dynasty China an invasion by Jurchens caused a schism of north and south. The Khmer Empire of Cambodia flourished during this century, while the Fatimids of Egypt were overtaken by the Ayyubid dynasty, China is under the Northern Song dynasty. Early in the century, Zhang Zeduan paints Along the River During the Qingming Festival and it will later end up in the Palace Museum, Beijing. In southeast Asia, there is conflict between the Khmer Empire and the Champa, Angkor Wat is built under the Hindu king Suryavarman II. By the end of the century the Buddhist Jayavarman VII becomes the ruler, Japan is in its Heian period. The Chōjū-jinbutsu-giga is made and attributed to Toba Sōjō and it ends up at the Kōzan-ji, Kyoto. In Oceania, the Tuʻi Tonga Empire expands to a greater area. Europe undergoes the Renaissance of the 12th century, the blast furnace for the smelting of cast iron is imported from China, appearing around Lapphyttan, Sweden, as early as 1150. Alexander Neckam is the first European to document the mariners compass, Christian humanism becomes a self-conscious philosophical tendency in Europe. Christianity is also introduced to Estonia, Finland, and Karelia, the first medieval universities are founded. Middle English begins to develop, and literacy begins to spread outside the Church throughout Europe, in addition, churchmen are increasingly willing to take on secular roles. By the end of the century, at least a third of Englands bishops also act as judges in secular matters. The Ars antiqua period in the history of the music of Western Europe begins. The earliest recorded miracle play is performed in Dunstable, England Gothic architecture and trouvère music begin in France, during the middle of the century, the Cappella Palatina is built in Palermo, Sicily, and the Madrid Skylitzes manuscript illustrates the Synopsis of Histories by John Skylitzes. Fire and plague insurance first become available in Iceland, and the first documented outbreaks of influenza there happens, the medieval state of Serbia state is formed by Stefan Nemanja and then continued by the Nemanjić dynasty. By the end of the century, both the Capetian Dynasty and the House of Anjou are relying primarily on mercenaries in their militaries, paid soldiers are available year-round, unlike knights who expected certain periods off to maintain their manor lifestyles

2.
13th century
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As a means of recording the passage of time, the 13th century was that century which lasted from 1201 through 1300 in accordance with the Julian calendar in the Common Era. In the history of European culture, this period is considered part of the High Middle Ages, 1202—Introduction of Liber Abaci by Fibonacci. 1202—Battle of Basian occurred on July 27, between Kingdom of Georgia and Seljuks, 1204—Fourth Crusade of 1202–1204 captures Zara for Venice and sacks Byzantine Constantinople, creating the Latin Empire. 1204—Fall of Normandy from Angevin hands to the French King, Philip Augustus, 1205—The Battle of Adrianople occurred on April 14,1205 between Bulgarians under Tsar Kaloyan of Bulgaria, and Crusaders under Baldwin I, the first emperor of the Latin Empire of Constantinople. 1206—Genghis Khan is declared Great Khan of the Mongols, 1213—France defeats the Spanish Kingdom of Aragon at the Battle of Muret. 1214—France defeats English and Imperial German forces at the Battle of Bouvines, 1215—King John signs Magna Carta at Runnymede. 1217–1221—Fifth Crusade captures Egyptian Ayyubid port city of Damietta, ultimately the Crusaders withdraw, 1221—Venice signs a trade treaty with the Mongol Empire. 1222—Andrew II of Hungary signs the Golden Bull which affirms the privileges of Hungarian nobility, 1233—Battle of Ganter, Ken Arok defeated Kertajaya, the last king of Kediri, thus established Singhasari kingdom Ken Arok ended the reign of Isyana Dynasty and started his own Rajasa dynasty. 1223-The Signoria, of the Republic of Venice is formed and consists of the Doge, the Minor Council, 1223—The Mongol Empire defeats various Russian principalities at the Battle of the Kalka River. 1223-Volga Bulgaria defeats the army of The Mongol Empire at the Battle of Samara Bend 1227 - Estonians are finally subjugated to German crusader rule during the Livonian Crusade, 1228-1229—Sixth Crusade under the excommunicated Frederick II Hohenstaufen, who returns Jerusalem to the Crusader States. 1228-1230- First clash between Gregory IX and Frederick II, 1226-1250- Dispute between the so-called second Lombard League and Frederick II. 1232—The Mongols besiege Kaifeng, the capital of the Jin dynasty, 1239–1250—Third conflict between Holy Roman Empire–Papacy. 1238—Sukhothai was the first capital of Sukhothai Kingdom, 1241—Mongol Empire defeats Hungary at the Battle of Mohi and defeats Poland at the Battle of Legnica. 1242—Russians defeat the Teutonic Knights at the Battle of Lake Peipus, 1244—Ayyubids and Khwarezmians defeat the Crusaders and their Arab allies at the Battle of La Forbie. 1249—End of the Portuguese Reconquista against the Moors, when King Afonso III of Portugal reconquers the Algarve, 1248–1254—Seventh Crusade captures Egyptian Ayyubid port city of Damietta, Crusaders ultimately withdraw. 1257—Baab Mashur Malamo established The Kingdom of Ternate in Maluku, 1258—Baghdad captured and destroyed by the Mongols, effective conclusion of the Caliphate 1259—Treaty of Paris. 1260—Toluid Civil War begins between Kublai Khan and Ariq Böke for the title of Great Khan, 1261—Byzantines under Michael VIII retake Constantinople from the Crusaders and Venice. 1262—Iceland was brought under Norwegian rule, with the Old Covenant 1265—Dominican friar and theologian, 1268—Fall of the Crusader State of Antioch to the Mamelukes

3.
14th century
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As a means of recording the passage of time, the 14th century was the century lasting from January 1,1301, to December 31,1400. Political and natural disasters ravaged Europe, as well as the four khanates of the Mongol Empire and this period is considered the height of chivalry and marks the beginning of strong separate identities for both England and France. The transition from the Medieval Warm Period to the Little Ice Age, beginning of the Ottoman Empire, early expansion into the Balkans. Early 14th century, Attributed to Kao Ninga Monk Sewing is made and it is now kept at The Cleveland Museum of Art. 1309, King Jayanegara succeeds Kertarajasa Jayawardhana as ruler of Majapahit, the Avignon papacy transfers the seat of the Popes from Italy to France The Great Famine of 1315-1317 kills millions of people in Europe. 1318, an Italian Franciscan monk, Mattiussi visited Sumatra, Java, in his record he described Majapahit kingdom. 1323, Malietoafaiga ordered cannibalism to be abolished in Tutuila, now known as American Samoa,1325, Forced out of previous locations, the Mexica found the city of Tenochtitlan 1328, Tribhuwana Wijayatunggadewi succeeds Jayanegara as ruler of Majapahit. Beginning of the Renaissance in Italy The death of the Ilkhan Abu Said in 1335, the Vijayanagara Empire is founded in South India by Harihara in 1336 The Hundred Years War begins when Edward III of England lays claim to the French throne. The French recruit troops and ships in Genoa, Monaco, Black Death kills around a third of the population of Europe. 1347, Adityawarman moved the capital of Dharmasraya and established the kingdom of Malayupura in Pagarruyung,1350, Hayam Wuruk, styled Sri Rajasanagara, succeeds Tribhuwana Wijayatunggadewi as ruler of Majapahit, his reign is considered the empires Golden Age. Under its military commander Gajah Mada, Majapahit stretches over much of modern-day Indonesia,1357, In the Battle of Bubat, the Sundanese royal family were massacred by the Majapahit army under the order of Gajah Mada. The death toll including Sundanese King Lingga Buana and the princess Dyah Pitaloka Citraresmi that committed suicide,1365, The Old Javanese text Nagarakertagama is written. The end of Mongol Yuan Dynasty in China and the beginning of the Ming Dynasty The Lollardy movement rises in England 1377, palembangs prince, Parameswara flees, eventually finding his way to Malacca and establishing it as a major international port. The Great Schism of the West begins in 1378, eventually leading to 3 simultaneous popes, singapore emerges for the first time as a fortified city and trading centre of some importance. Reunification of Poland under Władysław I of Poland Ciompi Revolt in Florence Peasants Revolt in England Islam reaches Terengganu, the Hausa found several city-states in the south of modern Niger. The Mali Empire expands westward and conquers Tekrur, the Scots win the Scottish Wars of Independence. 1392, Taejo of Joseon established Joseon Dynasty The Kalmar Union is established in 1397, uniting Norway, Sweden, iwan vault, Jamé Mosque of Isfahan, Isfahan, Persia, is built. Work begins on the Great Enclosure at Great Zimbabwe, built of un-cemented, dressed stone, the citys population is now between 10,000 and 40,000

4.
Berber calendar
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The Berber calendar is the agricultural calendar traditionally used by Berbers. It is also known as the fellaḥi, the calendar is utilized to regulate the seasonal agricultural works. It is used in lieu of the Islamic calendar, a calendar considered ill-adapted for agriculture because it does not relate to seasonal cycles. The current Berber calendar is a legacy of the Roman province of Mauretania Caesariensis, the latter calendar was used in Europe before the adoption of the Gregorian calendar, with month names derived from Latin. Berber populations previously used various indigenous calendars, such as that of the Guanche autochthones of the Canary Islands, however, relatively little is known of these ancient calendrical systems. Not much is known about the division of time among the ancient Berbers, some elements of a pre-Islamic, and almost certainly a pre-Roman calendar, emerge from some medieval writings, analyzed by Nico van den Boogert. Some correspondences with the traditional Tuareg calendar suggest that in antiquity there existed, with degree of diffusion. According to a 17th-century manuscript by Tomás Marín de Cubas, they computed their year, called Acano and it began in summer, when the sun enters in Cancer, on June 21, at the first conjunction they celebrated nine festival days for the crop. The name of one month is known in the native language. It seems it was the month of the year, corresponding to August. Such a name, in case it was made up by something like *wen that of + smet, may correspond, in the list of medieval Berber month names, with the ninth and tenth months, but data are too scarce for this hypothesis to be deepened. The agricultural Berber calendar still in use is almost certainly derived from the Julian calendar, the only slight discrepancy lies in that the extra day in leap years is not usually added at the end of February, but at the end of the year. Jean Servier has doubted that the calendar descends directly from the Julian calendar of the Latin era, there are standard forms for the names of the Amazigh calendar. The table below provides the forms used in Morocco, Algeria and Tunisia. In some areas they may be different due to communication and manipulation by the government. Moreover, pronunciation differs according to the region, the coldest period is made up by 20 white nights, from 12 to 31 dujamber, and 20 black nights, beginning on the first day of yennayer, corresponding to the Gregorian 14 January. The first day of the year is celebrated in various ways in the different parts of North Africa, a widespread tradition is a meal with particular foods, which vary from region to region, but in many zones it is provided by the sacrifice of an animal. In Algeria, such a holiday is celebrated even by people who dont use the Berber calendar in daily life

5.
Henry III of England
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Henry III, also known as Henry of Winchester, was King of England, Lord of Ireland and Duke of Aquitaine from 1216 until his death. The son of King John and Isabella of Angoulême, Henry assumed the throne when he was nine in the middle of the First Barons War. Cardinal Guala declared the war against the barons to be a religious crusade and Henrys forces, led by William Marshal, defeated the rebels at the battles of Lincoln. Henry promised to abide by the Great Charter of 1225, which limited royal power and his early rule was dominated first by Hubert de Burgh and then Peter des Roches, who re-established royal authority after the war. In 1230 the King attempted to reconquer the provinces of France that had belonged to his father. A revolt led by William Marshals son, Richard, broke out in 1232, following the revolt, Henry ruled England personally, rather than governing through senior ministers. He travelled less than previous monarchs, investing heavily in a handful of his palaces and castles. He married Eleanor of Provence, with whom he had five children, in a fresh attempt to reclaim his familys lands in France, he invaded Poitou in 1242, leading to the disastrous Battle of Taillebourg. After this, Henry relied on diplomacy, cultivating an alliance with Holy Roman Emperor Frederick II. Henry supported his brother Richard in his bid to become King of the Romans in 1256 and he planned to go on crusade to the Levant, but was prevented from doing so by rebellions in Gascony. The baronial regime collapsed but Henry was unable to reform a stable government, in 1263 one of the more radical barons, Simon de Montfort, seized power, resulting in the Second Barons War. Henry persuaded Louis to support his cause and mobilised an army, the Battle of Lewes occurred in 1264, where Henry was defeated and taken prisoner. Henrys eldest son, Edward, escaped captivity to defeat de Montfort at the Battle of Evesham the following year. Henry initially enacted a harsh revenge on the rebels, but was persuaded by the Church to mollify his policies through the Dictum of Kenilworth. Reconstruction was slow and Henry had to acquiesce to various measures, including suppression of the Jews, to maintain baronial. Henry died in 1272, leaving Edward as his successor and he was buried in Westminster Abbey, which he had rebuilt in the second half of his reign, and was moved to his current tomb in 1290. Some miracles were declared after his death but he was not canonised, Henry was born in Winchester Castle on 1 October 1207. He was the eldest son of King John and Isabella of Angoulême, little is known of Henrys early life

6.
Hebrew calendar
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The Hebrew or Jewish calendar is a lunisolar calendar used today predominantly for Jewish religious observances. It determines the dates for Jewish holidays and the public reading of Torah portions, yahrzeits. The present Hebrew calendar is the product of evolution, including a Babylonian influence, when to add it was based on observation of natural agriculture-related events in Israel. Through the Amoraic period and into the Geonic period, this system was displaced by the mathematical rules used today. The principles and rules were codified by Maimonides in the Mishneh Torah in the 12th century. Maimonides work also replaced counting years since the destruction of the Temple with the modern creation-era Anno Mundi, the era used since the Middle Ages is the Anno Mundi epoch. As with Anno Domini, the words or abbreviation for Anno Mundi for the era should properly precede the date rather than follow it, AM5777 began at sunset on 2 October 2016 and will end at sunset on 20 September 2017. The Jewish day is of no fixed length, the Jewish day is modeled on the reference to. there was evening and there was morning. In the creation account in the first chapter of Genesis, based on the classic rabbinic interpretation of this text, a day in the rabbinic Hebrew calendar runs from sunset to the next sunset. In most populated parts of the world this is always approximately 24 standard hours, halachically, a day ends and a new one starts when three stars are visible in the sky. The time between sunset and the time when the three stars are visible is known as bein hashmashot, and there are differences of opinion as to which day it falls into for some uses. This may be relevant, for example, in determining the date of birth of a child born during that gap, there is no clock in the Jewish scheme, so that the local civil clock is used. The civil clock is used only as a reference point – in expressions such as, Shabbat starts at. In Judaism, an hour is defined as 1/12 of the time from sunrise to sunset, so, during the winter, an hour can be less than 60 minutes. This proportional hour is known as a shaah zmanit, a Jewish hour is divided into 1080 halakim or parts. A part is 3⅓ seconds or 1/18 minute, the ultimate ancestor of the helek was a small Babylonian time period called a barleycorn, itself equal to 1/72 of a Babylonian time degree. These measures are not generally used for everyday purposes, instead of the international date line convention, there are varying opinions as to where the day changes. One opinion uses the antimeridian of Jerusalem, the weekdays start with Sunday and proceed to Saturday, Shabbat

7.
Islamic calendar
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The Islamic, Muslim, or Hijri calendar is a lunar calendar consisting of 12 months in a year of 354 or 355 days. It is used to date events in many Muslim countries and it is also used by Muslims to determine the proper days of Islamic holidays and rituals, such as the annual period of fasting and the proper time for the pilgrimage to Mecca. The Islamic calendar employs the Hijri era whose epoch was retrospectively established as the Islamic New Year of AD622, during that year, Muhammad and his followers migrated from Mecca to Yathrib and established the first Muslim community, an event commemorated as the Hijra. In the West, dates in this era are usually denoted AH in parallel with the Christian, in Muslim countries, it is also sometimes denoted as H from its Arabic form. In English, years prior to the Hijra are reckoned as BH, the current Islamic year is 1438 AH. In the Gregorian calendar,1438 AH runs from approximately 3 October 2016 to 21 September 2017, four of the twelve Hijri months are considered sacred, Rajab, and the three consecutive months of Dhū al-Qa‘dah, Dhu al-Ḥijjah and Muḥarram. As the lunar calendar lags behind the solar calendar by about ten days every gregorian year, the cycle repeats every 33 lunar years. Each month of the Islamic calendar commences on the birth of the new lunar cycle, traditionally this is based on actual observation of the crescent marking the end of the previous lunar cycle and hence the previous month, thereby beginning the new month. Consequently, each month can have 29 or 30 days depending on the visibility of the moon, astronomical positioning of the earth and weather conditions. However, certain sects and groups, most notably Dawoodi Bohra Muslims and Shia Ismaili Muslims, use a tabular Islamic calendar in which odd-numbered months have thirty days, in Arabic, the first day of the week corresponds with Sunday of the planetary week. The Islamic weekdays, like those in the Hebrew and Baháí calendars, the Christian liturgical day, kept in monasteries, begins with vespers, which is evening, in line with the other Abrahamic traditions. Christian and planetary weekdays begin at the following midnight, Muslims gather for worship at a mosque at noon on gathering day which corresponds with Friday. Thus gathering day is regarded as the weekly day of rest. A few others have adopted the Saturday-Sunday weekend while making Friday a working day with a midday break to allow time off for worship. Inscriptions of the ancient South Arabian calendars reveal the use of a number of local calendars, at least some of these calendars followed the lunisolar system. For Central Arabia, especially Mecca, there is a lack of epigraphical evidence, both al-Biruni and al-Masudi suggest that the Ancient Arabs used the same month names as the Muslims, though they also record other month names used by the pre-Islamic Arabs. Nevertheless, the Islamic position equating Nisan with Dhū al-Ḥijja has prevailed, for a comparison between the Islamic and pre-Islamic months, see Islamic and Jahili months. The Islamic tradition is unanimous in stating that Arabs of Tihamah, Hejaz, the forbidden months were four months during which fighting is forbidden, listed as Rajab and the three months around the pilgrimage season, Dhu al-Qa‘dah, Dhu al-Hijjah, and Muharram

8.
Japanese calendar
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Japanese calendar types have included a range of official and unofficial systems. At present, Japan uses the Gregorian calendar together with year designations stating the year of the reign of the current Emperor, the lunisolar Chinese calendar was introduced to Japan via Korea in the middle of the sixth century. After that, Japan calculated its calendar using various Chinese calendar procedures, but in 1873, as part of Japans Meiji period modernization, a calendar based on the solar Gregorian calendar was introduced. In Japan today, the old Chinese calendar is virtually ignored, celebrations of the Lunar New Year are thus limited to Chinese, Japan has had more than one system for designating years. Including The Chinese sexagenary cycle was introduced into Japan. It was often used together with era names, as in the 1729 Ise calendar shown above, now, though, the cycle is seldom used except around New Years. The era name system was introduced from China, and has been in continuous use since AD701. Each Emperors reign begins a new era, before 1868 era names were also declared for other reasons. Nengō are the means of dating years in Japan. It is also in use in private and personal business. The Japanese imperial year or kigen 紀元 is based on the date of the founding of Japan by Emperor Jimmu in 660 BC. It was first used in the calendar in 1873. However, it never replaced era names, and since World War II has been abandoned, the Western Common Era system has gradually come into common use since the Meiji period. Now, most people know it, as well as era names, the official dating system known as nengō 年号, strictly speaking, gengō 元号, has been in use since the late 7th century. Years are numbered within eras, which are named by the reigning Emperor, the nengō system remains in wide use, especially on official documents and government forms. The imperial year system was used from 1872 to the Second World War, Imperial year 1 was the year when the legendary Emperor Jimmu founded Japan –660 BC according to the Gregorian Calendar. Usage of kōki dating can be a nationalist signal, pointing out that the history of Japans imperial family is longer than that of Christianity, kōki 2600 was a special year. The 1940 Summer Olympics and Tokyo Expo were planned as anniversary events, the Japanese naval Zero Fighter was named after this year

9.
1260s
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The 1260s is the decade starting January 1,1260 and ending December 31,1269. In Asia, Kublai Khan was proclaimed the leader of the Mongol Empire. The Mamluks, led by their new sultan Baibars, quickly became a power in the Middle East by capturing a number of crusader states. The Empire of Nicaea succeeded in capturing Constantinople and the rest of the Latin Empire, in Europe, political strife and territorial disputes led to widespread warfare around the continent. England witnessed the Second Barons War, a war fought over the aristocracys disillusionment with King Henry IIIs attempts to maintain an absolute monarchy. Meanwhile, King Otakar II of Bohemia became the most powerful prince in Europe, in other developments, both Iceland and Greenland accepted the overlordship of Norway, but Scotland was able to repulse a Norse invasion and broker a favorable peace settlement. In Spain, the Reconquista continued as important cities were recaptured from the Moors. Political reforms were instituted in the procedures of the pope and the doges of Venice. Several important cultural achievements were made in the decade, including publication of Roger Bacons important scientific work Opus Majus, masterpieces of architecture and sculpture were completed at cathedrals around Europe, including the Cathedral of Chartres and Nicola Pisanos pulpits for the Duomo di Siena and Pisas Baptistery. In religion, the Sukhothai kingdom in Thailand adopted Buddhism as its official religion,1260 – Brian Ua Neill, King of the Irish, was slain by the Anglo-Normans at the Battle of Druim Dearg and his head severed and removed to the King of the Saxons in London. 1260 – The Baltic Samogatians and Curonians defeat the Teutonic knights in the Battle of Durbe,1263 – October – King Alexander III of Scotland fights a minor skirmish against King Haakon IV of Norway in the Battle of Largs. 1263 – The chieftains of the part of Iceland become the last to pledge fealty to the Norwegian king, bringing a more complete end to the Icelandic Commonwealth. 1260 – September 4 – The forces of King Manfred of Sicily, in league with the Ghibellines,1260 – War breaks out in the Valais as the Bishopric of Sion defends against an invasion by the County of Savoy. 1261 – Byzantine Empire reemerges, Latin empire brought down 1263 – Genoa captures the city of Chania on Crete from the Venetians,1264 – The Thuringian War of Succession ends. 1266 – February 26 – In the Battle of Benevento, an army led by Charles, Count of Anjou, Manfred is killed in the battle and Pope Clement IV invests Charles as king of Sicily and Naples. 1263 – King James I of Aragon conquers Crevillente, Spain from the Moors during the Reconquista,1264 – In Spain, King James I of Aragon reconquers the cities of Orihuela in Alicante and Elx in Valencia from the Moors, ending over 500 years of Islamic rule. 1265 – King Alfonso X of Castile captures the city of Alicante,1267 – King Afonso III of Portugal and King Alfonso X of Castile sign a treaty determining the southern border between Portugal and Spain as the Guadiana River, a border that remains to this day. 1260 – King Otakar II of Bohemia captures Styria from King Béla IV of Hungary in the Battle of Kressenbrunn,1261 – Béla IV of Hungary repels a Tatar invasion

10.
Hindu calendar
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Hindu calendar is a collective term for the various lunisolar calendars traditionally used in Hinduism. They adopt a similar underlying concept for timekeeping, but differ in their emphasis to moon cycle or the sun cycle, the names of months. A Hindu calendar is referred to as Panchanga. The ancient Hindu calendar is similar in design to the Jewish calendar. Early Buddhist communities of India adopted the ancient Indian calendar, later Vikrami calendar, Buddhist festivals continue to be scheduled according to a lunar system. The Buddhist calendar and the traditional calendars of Cambodia, Laos, Myanmar, Sri Lanka. Similarly, the ancient Jainism traditions have followed the lunisolar system as the Hindu calendar for festivals, texts. However, the Buddhist and Jaina timekeeping systems have attempted to use the Buddha, the Hindu calendar is also important to the practice of Hindu astrology and zodiac system, most of which it adopted from Greece, in centuries after the arrival of Alexander the Great. The Indian national calendar or Saka calendar was introduced in 1952 based on the traditional Hindu calendars and this study was one of the six ancient Vedangas, or ancillary science connected with the Vedas – the scriptures of Hinduism. The ancient Indian culture developed a time keeping methodology and calendars for Vedic rituals. David Pingree has proposed that the field of timekeeping in Jyotisha may have derived from Mesopotamia during the Achaemenid period. Ohashi states that this Vedanga field developed from actual astronomical studies in ancient India, timekeeping as well as the nature of solar and moon movements are mentioned in Vedic texts. For example, Kaushitaki Brahmana chapter 19.3 mentions the shift in the location of the sun towards north for 6 months. The Vikrami calendar is named after king Vikramaditya and starts in 57 BCE, Hindu scholars attempted to keep time by observing and calculating the cycles of sun, moon and the planets. These texts present Surya and various planets and estimate the characteristics of the respective planetary motion, other texts such as Surya Siddhanta dated to have been complete sometime between the 5th century and 10th century present their chapters on various planets with deity mythologies. The manuscripts of texts exist in slightly different versions, present Surya- and planets-based calculation. These vary in their data, suggesting that the text were open and they tracked the solar year by observing the entrance and departure of surya in the constellation formed by stars in the sky, which they divided into 12 intervals of 30 degrees each. Like other ancient human cultures, Hindus innovated a number of systems of which intercalary months became most used, as their calendar keeping and astronomical observations became more sophisticated, the Hindu calendar became more sophisticated with complex rules and greater accuracy

11.
Kali Yuga
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Kali Yuga is the last of the four stages the world goes through as part of the cycle of yugas described in the Sanskrit scriptures, within the present Mahayuga. The other ages are called Satya Yuga, Treta Yuga, Kali Yuga is associated with the demon Kali. The Kali of Kali Yuga means strife, discord, quarrel or contention, according to Puranic sources, Krishnas departure marks the end of Dvapara Yuga and the start of Kali Yuga, which is dated to 17/18 February 3102 BCE. According to the Surya Siddhanta, Kali Yuga began at midnight on 18 February 3102 BCE and this is also considered the date on which Lord Krishna left the earth to return to his heavenly abode. This information is placed at the temple of Bhalka, the place of this incident, according to the astronomer and mathematician Aryabhatta the Kali Yuga started in 3102 BCE. He finished his book “Aryabhattiya” in 499 CE, in which he gives the year of the beginning of Kali Yuga. He writes that he wrote the book in the year 3600 of the Kali Age at the age of 23. As it was the 3600th year of the Kali Age when he was 23 years old, and given that Aryabhatta was born in 476 CE, according to KD Abhyankar, the starting point of Kaliyuga is an extremely rare planetary alignment, which is depicted in the Mohenjo-Daro seals. Going by this alignment the year 3102 BCE is slightly off, the actual date for this alignment is February 7 of 3104 BCE. There is also sufficient proof to believe that Vrdhha Garga knew of precession at least by 500 BCE, Garga had calculated the rate of precession to within 30% of what the modern scholars estimate. The Kali Yuga is thought by some authors to last 6480 years although other durations have been proposed, hindus believe that human civilization degenerates spiritually during the Kali Yuga, which is referred to as the Dark Age because in it people are as far away as possible from God. Hinduism often symbolically represents morality as an indian bull, in Satya Yuga, the first stage of development, the bull has four legs, but in each age morality is reduced by one quarter. By the age of Kali, morality is reduced to only a quarter of that of the golden age, the Mahabharata War and the decimation of Kauravas thus happened at the Yuga-Sandhi, the point of transition from one yuga to another. A discourse by Markandeya in the Mahabharata identifies some of the attributes of Kali Yuga, in relation to rulers, it lists, Rulers will become unreasonable, they will levy taxes unfairly. Rulers will no longer see it as their duty to promote spirituality, or to protect their subjects, people will start migrating, seeking countries where wheat and barley form the staple food source. (Srimad-Bhagavatam With regard to relationships, Markandeyas discourse says, Avarice. Humans will openly display animosity towards each other, people will have thoughts of murder with no justification and will see nothing wrong in that. Lust will be viewed as acceptable and sexual intercourse will be seen as the central requirement of life

A page from a Tunisian calendar, showing the correspondence of 1 Yennayer ʿajmi (in red on bottom) with the 14 January of the Gregorian calendar. The writing on the bottom signals that it is ʿajmi New Year's Day and that al-lyali al-sud ("the black nights") are beginning.

Iḍ n innayr

Photo taken on 31 December 2007 near Tafraout (Morocco), with the writings aseggas ameggaz ("good year") in Tifinagh and bonne année 2959 ("good year 2959") in French. Note the 1-year mistake, as 2959 corresponds to the Gregorian year 2009.